Sizing fabric



Patented July 20, 1937 NITED STATES PATENT OFFICE SIZING FABRIC No Drawing. Application August 17, 1934,

Serial No. 740,297

' Claims.

This invention relates to the sizing of fabrics and more particularly to the sizing of fabrics with low-substituted cellulose ether derivatives of allphatic hydroxy acids.

In the old well-known and extensively practiced art of the sizing of textiles, the question of the sizing material is one of importance. The sizing materials used at the present time suffer from certain disadvantages. One of these is the rela- 10 tively low fastness to laundering.

This invention has as an object the provision of a method of treating fabrics to give them a greatly improved finish, as revealed by the appearance and feel.

A further object is the provision of a textile having a substantially permanent starch-like finish. Other objects will appear hereinafter.

These objects'are accomplished by the following invention wherein a fabric, thread, or yarn is impregnated with an aqueous caustic alkali solution of a cellulose ether of a hydroxy aliphatic acid, and particularly a cellulose ether of a cellulose glycollic acid, which cellulose other is insoluble in aqueous caustic alkali at ordinary temperature but soluble therein at low temperature, and the impregnated fabric, thread, or yarn thereafter treated with an acid to insolubilize the cellulose ether of the hydroxy aliphatic acid.

In carrying out the process of the present invention, the object to be impregnated, whether a textile fabric, a thread or yarn, is'treated with a solution of a low-substituted cellulose ether of a hydroxy aliphatic acid which ether is soluble in aqueous caustic alkali only on cooling. This particular type of cellulose ether of aliphatic hydroxy acid, which after once having been dissolved in alkali at low temperature, may be, without precipitation, warmed to room temperature, is described in U. S. Patent 2,060,056 of Nov. 10, 1936 in the name of Deane C. Ellsworth. The preparation of an example of these cellulose ethers of hydroxy fatty acids .is described below in order to exemplify the material to be used in accordance with the teachings of the present invention.

In an excess of 20% sodium hydroxide solution, one molar weight (162 parts) of oven dried cellulose (spruce sulfite pulp) in the form of sheets is steeped for 2 hours at 28 C. This is pressed out until its weight is 3 times that of the starting cellulose. The sheets are shredded or torn to crumbs in a shredder of suitable type at a temperature not exceeding 25 C. for 2 hours. The alkali cellulose so prepared is allowed to age or ripen in a covered can for 24 hours at 28 C. before reacting upon it with a solution of 0.6 mo]. parts) of sodium chloracetate in, a little water. Such a solution is conveniently prepared by dissolving 56.5 parts of chloracetic acid in 61 parts of water and neutralizing this with 50 parts of sodium bicarbonate. The reaction can best be carried out in an apparatus of the mixer or shredder type, equipped with a means for circulating warm and cold water thru the jacket of the mixer. The sodium chloracetate solution is kneaded in, and then the shredder is sealed air tight and the contents are warmed to 40-42 C. at which temperature reaction is maintained for 20 hours.

The product, which resembles the original alkali cellulose in appearance, is dispersed in 1836 parts of 6% NaOH, in which at room temperature it makes only an imperfect (fibrous) solution, but which solution, after being cooled to -6 to -10 C. and being again warmed to room temperature, is a beautiful, clear and transparent,

colorless or pale straw colored liquid of moderate viscosity similar to that of spinning viscose. It is fiber free but should be filtered to remove any extraneous matter.

It is to be noted that the cellulose ether thus prepared is insoluble in alkali at ordinary temperatures but soluble therein by cooling to approximately the freezing point.

Textile fabrics, threads, or yarns when treated with an alkaline solution of a low-substituted cellulose ether of a hydroxy fatty acid soluble in alkali only on cooling, suchas the low-substituted glycollic acid described above, and then treated with a dilute acid in order to coagulate the cellulose ether on the fabric, with or with.- out subsequent treatment with an aluminum or other salt, having imparted to them remarkable sizing effects. This finish is substantially permanent, i. e., it is not readily removed by laundering as is the case with starch finishes. Fabrics treated according to the processes of the present invention may be given a good luster by hot or cold calendering. Textiles treated with sizingagents made from starch, gums, sulfonated tallow, and with varieties of cellulose glycollic acid other than those described in the present invention are not nearly so laundry-fast. Thus, it is well known that sizes based on starch are readily removed from fabrics by a single washing, whereas washing has relatively little effect on fabrics sized according to the process of the present invention.

In treating textiles, including fabrics and yarns, according to the present invention, the materi is first impregnated with an alkaline solutio of the low-substituted cellulose ether of the hydroxy aliphatic acid. Aqueous solutions containing from 0.25% to glycollic acid and from 4% to 10% alkali are satisfactory. Solutions with less than 0.25% of the sizing agent have very little effect as sizes and solutions of above 10% concentration are too viscous for conven- 10 ien't application. At least 1% alkali based on the total solution, is required to dissolve the cellulose glycollic acid. Concentrations above 10% alkali have no advantage and tend to cause gelation of the cellulose glycollic acid. Thefabric or yarn to be treated may conveniently be run thru a bath of the cellulose glycollic acid solution and then thru squeeze rolls to remove the excess thereof. The cellulose glycollic acid is then coagulated on the fabric by running the fabric thru a bath of dilute sulfuric or acetic acid.

The fabric may next be dried or may first be treated with an aluminum or other heavy metal salt solution and then dried. In either case, a substantially permanent starch-like finish is imparted to the fabric which may be improved by hot or cold calendering.

A greater gloss can be obtained by impregnating the fabric under tension or by stretching the fabric after impregnation or by stretching during the precipitation of the cellulose glycollic acid.

The cellulose glycollic acid used in the process of the present invention differs from the forms of cellulose glycollic acid hitherto described in being insoluble in organic solvents, insoluble in water, insoluble in alkali at the ordinary tem- .perature, but soluble therein when cooled to a low temperature. The solution obtained by cooling can be warmed up to room temperature without coagulation or gelation and in different form is suitable for the treatment of textiles. The application is therefore limited to cellulose ethers of hydroxy aliphatic acids. and particularly to cellulose glycollic acids which are insoluble in alkali at normal temperature but soluble in alkali at low temperatures (5 to -20 0.), these cellulose ethers being characterized by having from 1 5' to V glycollic residues (CH2COOH) per glucose (Ce) unit.

Having outlined above the general principles of the invention,-the following examples thereof are added for purposes of illustration and not in limitation.

Example 1 55 Twenty-one g. of a cellulose glycollic acid prepared according to the procedure given above and containing fl glycollic acid group per glucose unit was thoroly mixed with 132 g. of watenand allowed to stand 1 hour to insure complete wetting. Eighteen g. of sodium hydroxide dissolved in 129 g. water was added, the whole thoroly mixed, then cooled to -20 C. The mass was frozen solid. When it was warmed up to room temperature, a solution was obtained which was substantially free of fibers of cellulose.

This solution contained 7% cellulose glycollic acid and approximately 6% alkali. It was used for impregnating a piece of unfinished 48/48 cotton fabric. After impregnation the fabric was 0 run thru squeeze rolls to remove excess solution and then immersed for 2 minutes in 8% sulfuric acid, again squeezed out and immersed for 3 minutes in 5% aluminum sulfate -solution, squeezed out and dried'by ironing. The treated 75 fabric possessed a linen-like feel and appear- 2,os7,2s'r

'ance and the finish was not removed by boiling for V hour in 0.5% soap solution.

Instead of the sulfuric acid used in this and the following examples, acetic, hydrochloric or phosphoric acid may be employed, and, instead of aluminum sulfate, alum or a salt of iron, tin,

zinc, cerium, lead, copper, or chromium may be used.

The following specific first regeneration baths may be employed:

(1) Sulfuric acid- (0.5 molar) +sodium chloride (1.0 molar).

Sulfuric acid (0.5 molar) +ammonium sulfate (0.5) molar).

Sulfuric acid (0.5 molar) +magnesium sulfate (0.1 molar).

Sulfuric acid (0.5 molar) +potassium chromium sulfate (0.1 molar).

Sulfuric acid (0.5 molar) +stannic ammonium chloride (0.1 molar).

Acetic acid (2.0 molar) +sodium acetate (0.5 molar).

Sodium sulfate (2.0 molar) followed by (b) sulfuric acid (0.5 molar).

Sulfuric acid (8%) +sodium sulfate (26%) +dextrose (4%).

Sulfuric acid (13%) +sodium sulfate Example 2 A sample of cotton voile was treated according to the procedure in Example 1. A substantially permanent organdy effect was obtained.

Example 3 A piece of unfinished cotton voile was treated according to the procedure of Example 3 and an organdy finish was obtained somewhat less stifi than thatobtained in Example 2.

Emample 5 A portion of the solution described in Example 1 was diluted to 3.5% cellulose glycollic acid and 3% sodium hydroxide and used. to treat a piece of unfinished 48/48 cotton fabric. After treatment with the cellulose glycollic acid solution, the fabric was run thru squeeze rolls, then into a single bath containing 6% sulfuric acid and 3.5% aluminum sulfate. A substantially permanent linen-like effect was obtained.

Example 6 An unfinished cotton voile was treated according to Example 5. A substantially permanent organdyeifect was obtained. 7

Example 7 Twenty-one g. of cellulose glycollic acid prepared according to the procedure given above and containing glycollic acid group per glucose unit was thoroly mixed with 130 g. of water and allowed to stand 1 hour to insure complete wetting. One hundred-thirty g. of a solution containing 18 g. sodium hydroxide was-added and the mass cooled to --20 C. The mixture froze solid. On warming to room temperature, a solution was obtained which was free from fibers.

This solution was diluted to 3 cellulose glycollic acid and used to impregnate an unfinished 48/48 cotton fabric. The fabric was then immersed for 2 minutes in sulfuric acid, run thru squeeze rolls and into a bath of 5% aluminum sulfate for 3 minutes. It was rinsed and dried by ironing. A starch-like finish was obtained which was highly resistant to laundering. 1

Example 8 Twenty g.' of the cellulose glycollic acid described in Example 1 was mixed with 90 g. water, allowed to stand'until thoroly wet, then chilled. A cold solution of 20 g. sodium hydroxide in 90 g. water was added and the whole thoroly mixed. One hundred eighty g. of finely cracked ice was then added and the mass stirred vigorously. The temperature went down to about C. When it had warmed up to room temperature practically all of the cellulose glycollic acid had gone into solution.

This solution was used to impregnate an unfinished 80/60 cotton fabric. (If desired, the solution may be filtered before using.) After running the impregnated fabric thru squeeze rolls to remove excess solution, it was immersed in a solution of 5% sulfuric acid, again run thru squeeze rolls,'and into a bath of 5% aluminum sulfate, rinsed, and dried by ironing. A substantially permanent starch-like finish was obtained.

Example 9 A cellulose glycollic acid containing glycollic acid group per glucose unit was dissolved in 6% caustic according to the procedure of Example 1, the final solution containing 3% cellulose glycollic acid. An 80/60 cotton fabric was impregnated with this solution, run thru squeeze rolls, then into a solution of 10% sulfuric acid. It was finally rinsed thoroly and dried by ironing. A pleasant linen-like finish was obtained which was substantially permanent to laundering.

The concentration of alkali may vary from 1% to 11%, depending upon the extent of substitution of the cellulose and upon the degree of degradation thereof. Sodium hydroxide represents the preferred alkali and the cellulose glycollic acid may be dissolved at a temperature from --5 to 20 0., or even lower, if the freezing point of the solution is lower than -20 C.

As stated above, the viscosity of solutions of cellulose glycollic acid beyond 10% limits their application which may be effected by any of the methods commonly used by the textile trade for similar material.

The cellulose glycollic acid may be fixed on the fabric by acids alone, by acids followed by metal salt solutions, or by a single bath containing both acid and metal salt in solution. The results obtained by the first and third modifications are not as good as those obtained by the second application of acid followed by salt solution. Sulfuric acid followed by alum or aluminum sulfate represents the best combination of fixing baths. In the fixing bath the acid concentration may vary from 1% to 30%, and the concentration of the metal salt may vary from 5% upwards.

' After the impregnation and fixing of the cellulose glycollic acid the fabrics are preferably rinsed thoroly in hot and cold water and given a light soaping.v The dryingand calendering operations may follow the methods commonly used by the textile trade.

Cellulose glycollic acid may be applied to any of the fabrics or yarns to which the ordinary starch, gum, or tallow sizes are applied. These includes all types of cotton yarns and fabrics. Cellulose glycollic acid may also be applied to, linen, wool, silk, or rayon yarns or fabrics, or to wool or fur felts.

The above description and examples are in tended to be illustrative only. Any modification of or variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims;

I claim:

1. Process of sizing fabrics with cellulose glycollic acid soluble in aqueous caustic soda at low temperature but insoluble at ordinary temperature, which comprises impregnating a cotton fabric with a solution containing approximately 7% of said cellulose glycollic acid, said solution also containing approximately 6% caustic soda, removing excess solution from the fabric and coagulating the cellulose glycollic acid on the fabric by treatment with 8% sulfuric acid, followed by treatment with 5% aluminum sulfate solution, and thereafter drying.

2. Process of sizing fabrics which comprises impregnating a cotton fabric with a dilute aqueous caustic alkali solution of cellulose glycollic acid undissolved by aqueous caustic soda at ordinary temperature but dissolved therein at low temperature, and thereafter coagulating and fixing the cellulose ether on the fabric by consecutive exposure to acid and salt solutions.

3. Process of sizing fabrics which comprises impregnating a cotton fabric with a dilute aqueous caustic soda solution of cellulose gly-.

collic acid undissolved by aqueous caustic soda at ordinary temperature'but dissolved therein at low temperature, and thereafter coagulating and fixing the cellulose ether on the fabric by consecutive exposure to acid and salt solutions.

4. Process of sizing fabrics with cellulose glycollic acid soluble in aqueous caustic soda at low temperature but insoluble at ordinary temperature, which comprises impregnating a cotton fabric with a dilute aqueous caustic soda solution of said cellulose glycollic acid, and thereafter coagulating the cellulose glycollic acid on the fabric.

5. Process of sizing fabrics with cellulose ethers of hydroxy aliphatic acids, which ethers are soluble in caustic soda at low temperature but insoluble at ordinary temperature, which comprises impregnating a cotton fabric with a dilute aqueous caustic soda solution of said ether, and thereafter coagulating said ether on the fabric.

6. A fibrous material sized with a low-substi tuted cellulose ether of a hydroxy fatty acid, said ether being insoluble in caustic alkali at room temperature but soluble therein at temperatures approximating the freezing point.

7. A fibrous material sized with a low-substituted cellulose ether of a hydroxy fatty acid,

said ether being insoluble in caustic alkali at room temperature but soluble therein at temperatures below 5 C.

8. A fibrousmaterial sized with a low-substituted cellulose glycollic acid, said cellulose glycollic acid being insoluble in caustic alkali at room temperature but soluble therein at temperatures below 5 C.

9. A textile material sized with a low substituted cellulose glycolic acid, said cellulose glycolic'acid being insoluble in caustic alkali at room temperature but solubilized by cooling to temperatures below 5 C. therein. v k

10. A textile material sized with a low substituted cellulose ether of a hydroxy fatty acid, said ether being insoluble in caustic alkali at room temperature but soluble therein after cooling to temperatures below 5 C.

11. The process of sizing cotton thread with cellulose ethers oi! hydroxy aliphatic acids, which ethers are soluble in caustic soda after cooling to' 5 C. but insoluble at ordinary temperature, which comprises impregnating a cotton thread with a dilute aqueous caustic soda solution of said ether and thereafter coagulating said ether on the fabric.

12. The process of sizing cotton fiber with cellulose glycolic acid, which glycolic acid is soluble in 6% aqueous caustic soda after cooling to 5 C. but insoluble therein at ordinary temperature, which comprises impregnating the a cotton fiber with a 6% aqueous caustic soda sospruce sulfite pulp in the form of sheets in an excess of 20% sodium hydroxide solution for two hours at 28 C., pressing to a weight of three times that of the starting cellulose, shredding the cresultant at a temperature not-exceeding 25 C. for 2 hours, aging the shredded material in a covered container for 24 hours at 28 C.; reacting the aged material with 70 parts of 0.6 m01.sodium chloracetate solution at a temperature not exceeding 42 C. for 20 hours, and thereafter coagulating the cellulose ether on the fiber.

14. A sized cotton fiber obtainable by impregnating the same with a 6% aqueous caustic soda solution of a cellulose glycollic acid undissolved by 6% aqueous caustic soda at ordinary temperature, but dissolved therein after cooling to 5 C., such a cellulose ether being obtainable by steeping 162 parts of oven dried spruce sulfite pulp in the form of sheets in an excess of 20% sodium hydroxide solution for 2 hours at 28 C., pressing to a weight of three times that of the starting cellulose, shredding the resultant at a temperature not exceeding 25 C. for 2 hours, aging the shredded material in a covered container for 24 hours at 28 C., reacting the aged material with 70 parts of 0.6 mol. sodium chloracetate solution at a temperature not exceeding 42 C. for 20 hours, and thereafter coagulating the cellulose other on the fiber.

15. The process of sizing cotton fiber which comprises impregnating the same with a 6% aqueous caustic soda solution of a cellulose glycollic acid undissolved by 6% aqueous caustic soda at ordinary temperature, but dissolved therein after cooling'to 5 C., such a cellulose ether being obtainable bysteeping 162 parts of oven dried spruce sulfite pulp in the form of sheets in an excess of 20% sodium hydroxide solution for two hours at 28 C., pressing to a weight of three 'times that of the starting cellulose, shredding the resultant at a temperature not exceeding 25 C. for 2 hours, aging the shredded material in a covered container for 24 hours at 28 C., reacting the aged material with 70 parts of 0.6 mol. sodium chloracetate solution at a temperature not exceeding 42 C. for 20 hours, and thereafter coagulating the cellulose ether on the fiber by treatment with an acid of the group consisting of acetic, hydrochloric, phosphoric and sulfuric, and thereafter treating the resultant with a solution of a salt of a metal of the group consisting of aluminum, iron, tin, zinc, cerium, lead, copper and chromium.

Emma K. BOLTON. 

